Display device

ABSTRACT

A display device includes a non-display area adjacent a display area, a thin film transistor, a display element, a thin film encapsulation layer, an organic insulating layer, a power voltage line, and a protective layer. The thin film transistor is on the display area and is connected to the display element. The thin film encapsulation layer covers the display element. The organic insulating layer is between the thin film transistor and display element and extends to the non-display area. The organic insulating layer includes a central portion corresponding to the display area, an outer portion surrounding the central portion, and a division region dividing the central portion and the outer portion and surrounding the display area. The power voltage line is in the non-display area and includes a portion corresponding to the division region. The protective layer covers an upper surface of the power voltage line in the division region.

CROSS-REFERENCE TO RELATED APPLICATION

This is a continuation application based on currently pending U.S.patent application Ser. No. 16/193,013, filed on Nov. 16, 2018, thedisclosure of which is incorporated herein by reference in its entirety.U.S. patent application Ser. No. 16/193,013 is a continuationapplication of U.S. patent application Ser. No. 15/811,838, filed Nov.14, 2017, now U.S. Pat. No. 10,134,829, issued Nov. 20, 2018, thedisclosure of which is incorporated herein by reference in its entirety.U.S. Pat. No. 10,134,829 claims priority benefit of Korean PatentApplication No. 10-2016-0156592, filed on Nov. 23, 2016 in the KoreanIntellectual Property Office, the disclosure of which is incorporatedherein by reference in its entirety for all purposes.

BACKGROUND 1. Field

One or more embodiments described herein relate to a display device.

2. Description of the Related Art

A variety of flat-panel displays have been developed. These displaystend to be lightweight and have a slim profile with low powerconsumption. In order to enhance aesthetics and the viewing experience,attempts have been made to reduce the size of non-display areas of thesedisplays.

SUMMARY

In accordance with one or more embodiments, a display device includes asubstrate including a non-display area adjacent to a display area; athin film transistor on the display area and a display elementelectrically connected to the thin film transistor; a thin filmencapsulation layer covering the display element; an organic insulatinglayer between the thin film transistor and the display element andextending to the non-display area, the organic insulating layerincluding a central portion corresponding to the display area, an outerportion surrounding the central portion, and a division region dividingthe central portion and the outer portion and surrounding the displayarea; a power voltage line in the non-display area and including aportion corresponding to the division region; and a protective layercovering an upper surface of the power voltage line in the divisionregion. The protective layer may include an inorganic insulatingmaterial.

The display device may include a driving voltage line in the displayarea and electrically connected to the thin film transistor, wherein thedisplay element may includes: a pixel electrode, an opposite electrodefacing the pixel electrode, and an intermediate layer between the pixelelectrode and the opposite electrode, and wherein the organic insulatinglayer is between the driving voltage line and the pixel electrode. Thepower voltage line may include a first conductive layer; and a secondconductive layer on the first conductive layer and contacting the firstconductive layer. An end portion of the second conductive layer for thedivision region may cover a lateral surface of a portion of the firstconductive layer corresponding to the division region.

The display device may include a lower driving voltage line and an upperdriving voltage line in the display area and electrically connected tothe thin film transistor; and an insulating layer between the lowerdriving voltage line and the upper driving voltage line, the insulatinglayer including a contact hole to connect the lower driving voltage lineand the upper driving voltage line. The insulating layer may include anorganic insulating material.

The first conductive layer may include a same material as the lowerdriving voltage line, and the second conductive layer may include a samematerial as the upper driving voltage line. At least one of the firstconductive layer or the second conductive layer may be a multi-layer,and the multi-layer may include a first layer including titanium, asecond layer including aluminum, and a third layer including titanium.

The thin film encapsulation layer includes at least one inorganicencapsulation layer and at least one organic encapsulation layer, and aportion of the inorganic encapsulation layer corresponding to thedivision region may be covered with the thin film encapsulation layer.The protective layer may cover a portion of an upper surface of at leastone of the central portion or the outer portion of the organicinsulating layer.

The power voltage line may be below the organic insulating layer. Thecentral portion and the outer portion of the organic insulating layermay contact an upper surface of the power voltage line.

The display device may include a pad portion corresponding to one edgeof the substrate, wherein the power voltage line includes a connectionportion extending from one side of the display area to the pad portionand wherein at least a portion of the connection portion crosses thedivision region. The display device may include a dam inside thedivision region and surrounding the display area. The dam may be spacedapart from the central region and the outer region of the organicinsulating layer.

The display device may include an additional insulating layer includinga first insulating portion and a second insulating portion respectivelyover the central portion and the outer portion, wherein the additionalinsulating layer including a separation region corresponding to thedivision region. The display element may include a pixel electrode, anopposite electrode facing the pixel electrode, and an intermediate layerbetween the pixel electrode and the opposite electrode, and wherein theintermediate layer includes an emission layer.

The display device may include a pixel-defining layer includes anopening exposing the pixel electrode, wherein the additional insulatinglayer includes a same material as the pixel-defining layer. The powervoltage line may include a first power voltage line and a second powervoltage line to receive different voltages, the central portion of theorganic insulating layer may include an auxiliary division regionbetween a portion of the first power voltage line and a portion of thesecond power voltage line and may overlap the portion of the first powervoltage line and the portion of the second power voltage line.

BRIEF DESCRIPTION OF THE DRAWINGS

Features will become apparent to those of skill in the art by describingin detail exemplary embodiments with reference to the attached drawingsin which:

FIG. 1 illustrates an embodiment of a display device;

FIGS. 2A and 2B illustrate embodiments of a pixel;

FIG. 3 illustrates a view taken along section line in FIG. 1;

FIG. 4 illustrates an embodiment of a power line and second insulatinglayer;

FIG. 5 illustrates an embodiment of portion V in FIG. 4 including apull-off area;

FIG. 6 illustrates a view taken along section line VI-VI′ in FIG. 5;

FIG. 7 illustrates a view taken along section line VII-VII in FIG. 5;

FIG. 8 illustrates a view of a modified embodiment of the view in FIG.7; and

FIG. 9 illustrates a view of a modified embodiment of the view in FIG.5.

DETAILED DESCRIPTION

Example embodiments are described with reference to the drawings;however, they may be embodied in different forms and should not beconstrued as limited to the embodiments set forth herein. Rather, theseembodiments are provided so that this disclosure will be thorough andcomplete, and will convey exemplary implementations to those skilled inthe art. The embodiments (or portions thereof) may be combined to formadditional embodiments

In the drawings, the dimensions of layers and regions may be exaggeratedfor clarity of illustration. It will also be understood that when alayer or element is referred to as being “on” another layer orsubstrate, it can be directly on the other layer or substrate, orintervening layers may also be present. Further, it will be understoodthat when a layer is referred to as being “under” another layer, it canbe directly under, and one or more intervening layers may also bepresent. In addition, it will also be understood that when a layer isreferred to as being “between” two layers, it can be the only layerbetween the two layers, or one or more intervening layers may also bepresent. Like reference numerals refer to like elements throughout.

When an element is referred to as being “connected” or “coupled” toanother element, it can be directly connected or coupled to the anotherelement or be indirectly connected or coupled to the another elementwith one or more intervening elements interposed therebetween. Inaddition, when an element is referred to as “including” a component,this indicates that the element may further include another componentinstead of excluding another component unless there is differentdisclosure.

FIG. 1 illustrates an embodiment of a display device which includes adisplay unit 1 over a substrate 100. The display unit 1 includes aplurality of pixels P, each pixel connected to a respective one of aplurality of data lines DL extending in a first direction and arespective one of a plurality of scan lines SL extending in a seconddirection crossing the first direction. Each pixel P is also connectedto a respective one of a plurality of driving voltage lines PL extendingin the first direction.

The pixels P emit light of a plurality of colors, e.g., red, green,blue, and/or white light from, for example, organic light-emittingdiodes (OLEDs). The display unit 1 provides a predetermined image in adisplay area DA based on light emitted from the pixels P. Each pixel Pmay be considered, for example, a sub-pixel emitting one of red, green,blue, or white light as described above.

A non-display area NDA is outside the display area DA. For example, thenon-display area NDA may surround the display area DA. The non-displayarea NDA is a region in which the pixels P are not arranged and does notprovide an image. A first power voltage line 10 and a second powervoltage line 20, which respectively apply different power voltages, maybe arranged in the non-display area NDA.

The first power voltage line 10 may include a first main voltage line 11and a first connection line 12 corresponding to one side of the displayarea DA. For example, when the display area DA is rectangular, the firstmain voltage line 11 may correspond to one side of the display area DA.The first main voltage line 11 may be parallel to one of the sides andhave a length equal to or greater than the length of the one of thesides. One side corresponding to the first main voltage line 11 may beadjacent to a pad portion 30.

The first connection line 12 extends from the first main voltage line 11in a first direction. For example, the first connection line 12 mayextend in the first direction in a pull-off area POA. The pull-off areaPOA may be, for example, a region ranging from the pad portion 30 to oneof the sides of the display area DA adjacent to the pad portion 30. Thefirst direction may be, for example, a direction from the display areaDA to the pad portion 30. The first connection line 12 may be connectedto the pad portion 30, for example, a first pad end 32.

A second power voltage line 20 may include a second main voltage line 21and a second connection line 22. The second main voltage line 21 maypartially surround the display area DA. Opposite ends of the first mainvoltage line 11 and the second connection line 22 may extend from thesecond main voltage line 21 to the pad portion 30 in the firstdirection. For example, when the display area DA is rectangular, thesecond main voltage line 21 may extend along the opposite ends of thefirst main voltage line 11 and other or remaining sides of the displayarea DA other than the side adjacent to the first main voltage line 11.The second connection line 22 extends parallel to the first connectionline 12 in the first direction in the pull-off area POA and is connectedto the pad portion 30, for example, a second pad end 32.

The pad portion 30 corresponds to one end of the substrate 100, is notcovered by an insulating layer, etc., but is exposed, and may beconnected to a controller via a flexible printed circuit board (FPCB),etc. A signal or power of the controller is provided to the displaydevice via the pad portion 30.

The first power voltage line 10 provides a first power voltage ELVDD toeach pixel P. The second power voltage line 20 provides a second powervoltage ELVSS to each pixel P. For example, the first power voltageELVDD may be provided to each pixel P via the driving voltage line PLconnected to the first power voltage line 10. The second power voltageELVSS is provided to a cathode of an OLED of each pixel P. In this case,the second main voltage line 21 of the second power voltage line 20 maybe connected to the cathode of the OLED in the non-display area NDA.

A scan driver provides a scan signal to the scan lines SL and a datadriver provides data signals to the data lines DL. The scan driver andthe data driver may be in the non-display area NDA.

FIGS. 2A and 2B illustrate embodiments of a pixel, which, for example,may be representative of the pixels P in the display device of FIG. 1.Referring to FIG. 2A, each pixel P includes a pixel circuit PC connectedto an OLED. The pixel circuit PC is connected to the scan line SL andthe data line DL.

The pixel circuit PC includes a driving thin film transistor (TFT) T1, aswitching TFT T2, and a storage capacitor Cst. The switching TFT T2 isconnected to the scan line SL and the data line DL, and transfers a datasignal Dm to the driving TFT T1 via the data line DL based on a scansignal Sn from the scan line SL.

The storage capacitor Cst is connected to the switching TFT T2 and thedriving voltage line PL, and stores a voltage corresponding to adifference between a voltage transferred from the switching TFT T2 andthe first power voltage ELVDD (or a driving voltage) supplied via thedriving voltage line PL.

The driving TFT T1 is connected to the driving voltage line PL and thestorage capacitor Cst, and may control a driving current flowing throughthe OLED from the driving voltage line PL based on the voltage stored inthe storage capacitor Cst. The OLED may emit light having predeterminedbrightness based on the driving current. The pixel circuit PC in FIG. 2Aincludes two TFTs and one storage capacitor. The pixel circuit may havea different number of TFTs and/or capacitors in another embodiment.

Referring to FIG. 2B, the pixel circuit PC may include the driving andswitching TFTs T1 and T2, a compensation TFT T3, a first initializationTFT T4, a first emission control TFT T5, a second emission control TFTT6, and a second initialization TFT T7. Each pixel P in FIG. 2B includessignal lines SLn, SLn-1, EL, and DL, an initialization voltage line VL,and a driving voltage line PL. In one embodiment, at least one of thesignal lines SLn, SLn-1, EL, and DL, or the initialization voltage lineVL may be shared by adjacent pixels.

A drain electrode of the driving TFT T1 may be electrically connected toan OLED via the second emission control TFT T6. The driving TFT T1receives a data signal Dm and supplies a driving current to the OLEDbased on a switching operation of the switching TFT T2.

A gate electrode of the switching TFT T2 is connected to the first scanline SLn, and a source electrode of the switching TFT T2 is connected tothe data line DL. A drain electrode of the switching TFT T2 may beconnected to a source electrode of the driving TFT T1 and simultaneouslyconnected to the driving voltage line PL via the first emission controlTFT T5.

The switching TFT T2 is turned on and performs an operation oftransferring a data signal Dm from the data line DL to the sourceelectrode of the driving TFT T1 based on a first scan signal Sn from thefirst scan line SLn.

A gate electrode of the compensation TFT T3 may be connected to thefirst scan line SLn. A source electrode of the compensation TFT T3 maybe connected to the drain electrode of the driving TFT T1 andsimultaneously connected to the pixel electrode of the OLED via thesecond emission control TFT T6. A drain electrode of the compensationTFT T3 may be connected to one electrode of the storage capacitor Cst, asource electrode of the first initialization TFT T4, and the gateelectrode of the driving TFT T1, simultaneously. The compensation TFT T3is turned on, based on a first scan signal Sn from the first scan lineSLn, to diode-connect the driving TFT Ti by connecting the gateelectrode and the drain electrode of the driving TFT T1.

A gate electrode of the first initialization TFT T4 may be connected toa second scan line (a previous scan line) SLn-1. A drain electrode ofthe first initialization TFT T4 may be connected to the initializationvoltage line VL. A source electrode of the first initialization TFT T4may be connected to one of the electrodes of the storage capacitor Cst,the drain electrode of the compensation TFT T3, and the gate electrodeof the driving TFT T1, simultaneously. The first initialization TFT T4may be turned on, based on a second scan signal Sn-1 from the secondscan line SLn-1, to perform an operation of initializing the voltage ofthe gate electrode of the driving TFT T1 based on an initializationvoltage VINT supplied to the gate electrode of the driving TFT T1.

A gate electrode of the first emission control TFT T5 may be connectedto an emission control line EL. A source electrode of the first emissioncontrol TFT T5 may be connected to the driving voltage line PL. A drainelectrode of the first emission control TFT T5 is connected to thesource electrode of the driving TFT T1 and the drain electrode of theswitching TFT T2, simultaneously.

A gate electrode of the second emission control TFT T6 may be connectedto an emission control line EL. A source electrode of the secondemission control TFT T6 may be connected to the drain electrode of thedriving TFT T1 and the source electrode of the compensation TFT T3. Adrain electrode of the second emission control TFT T6 may beelectrically connected to the pixel electrode of the OLED. The firstemission control TFT T5 and the second emission control TFT T6 aresimultaneously turned on based on an emission control signal En from theemission control line EL. When transistors TFT T5 and TFT T6 are turnedon, the first power voltage ELVDD is transferred to the OLED and drivingcurrent flows through the OLED.

A gate electrode of the second initialization TFT T7 may be connected tothe second scan line SLn-1. A source electrode of the secondinitialization TFT T7 may be connected to the pixel electrode of theOLED. A drain electrode of the second initialization TFT T7 may beconnected to the initialization voltage line VL. The secondinitialization TFT T7 may be turned on to initialize the pixel electrodeof the OLED based on a second scan signal Sn-1 from the second scan lineSLn-1.

The first initialization TFT T4 and the second initialization TFT T7 areconnected to the second scan line SLn-1 in FIG. 2B. In one embodiment,the first initialization TFT T4 may be connected to the second scan lineSLn-1 and driven based on a second scan signal Sn-1. Also, the secondinitialization TFT T7 may be connected to a separate signal line (e.g. anext scan line) and driven based on a signal from a corresponding scanline.

Another electrode of the storage capacitor Cst may be connected to thedriving voltage line PL. One electrode of the storage capacitor Cst maybe connected to the gate electrode of the driving TFT T1, the drainelectrode of the compensation TFT T3, and the source electrode of thefirst initialization TFT T4, simultaneously.

The other electrode (e.g. cathode) of the OLED receives the second powervoltage ELVSS (or a common power voltage). The OLED emits light based onthe driving current from the driving TFT T1. The circuit design and/ornumber of TFTs and capacitors of the pixel circuit PC may be differentin another embodiment.

FIG. 3 illustrates a cross-sectional view of an embodiment of a pixel ofthe display device taken along line in FIG. 1. FIG. 3 illustrates thefirst and second TFTs T1 and T2 and the storage capacitor Cst of thepixel circuit PC of each pixel described with reference to FIGS. 2A and2B. For convenience, description is made according to a stacked order inFIG. 3.

Referring to FIG. 3, a buffer layer 101 is on the substrate 100, and thedriving and switching TFTs T1 and T2 and the storage capacitor Cst areover the buffer layer 101. The substrate 100 may include, for example, aglass material or a plastic material including polyethyleneterephthalate (PET), polyethylene napthalate (PEN), or polyimide (PI).When the substrate 100 includes a plastic material, the substrate 100may have greater flexibility than when the substrate 100 includes aglass material. The buffer layer 101 including SiOx and/or SiNx may beon the substrate 100 to prevent penetration of impurities.

The driving TFT T1 includes a driving semiconductor layer Act1 and thedriving gate electrode G1. The switching TFT T2 includes a switchingsemiconductor layer Act2 and the switching gate electrode G2. A firstgate insulating layer 103 is between the driving semiconductor layerActl and the driving gate electrode G1 and between the switchingsemiconductor layer Act2 and the switching gate electrode G2. The firstgate insulating layer 103 may include an inorganic insulating materialsuch as SiOx, SiNx, and SiON.

The driving semiconductor layer Actl and the switching semiconductorlayer Act2 may include polycrystalline silicon. The drivingsemiconductor layer Actl includes a driving channel region C1. A drivingsource region Si and a driving drain region D1 are at opposite sides ofthe driving channel region C1. The driving channel region C1 overlapsthe driving gate electrode G1 and is not doped with impurities. Thedriving source region S1 and the driving drain region D1 are doped withimpurities. The switching semiconductor layer Act2 may include aswitching channel region C2. A switching source region S2 and aswitching drain region D2 are at opposite sides of the switching channelregion C2. The switching channel region C2 overlaps the switching gateelectrode G2 and is not doped with impurities. The switching sourceregion S2 and the switching drain region D2 are doped with impurities.

The driving and switching gate electrodes G1 and G2 may include, forexample, Mo, Al, Cu, and Ti and may have a single layer or amulti-layer. For example, driving and switching gate electrodes G1 andG2 may include a single layer including Mo.

The source and drain regions of the TFTs may correspond to a sourceelectrode and a drain electrode of the TFT, respectively. Thus, theterms source region and drain region may be used instead of sourceelectrode and drain electrode.

In an embodiment, the storage capacitor Cst may overlap the driving TFTT1. In this case, areas of the storage capacitor Cst and the driving TFTmay be increased and a high-quality image may be provided. For example,the driving gate electrode G1 may serve as a first storage capacitorplate CE1 of the storage capacitor Cst. A second storage capacitor plateCE2 may overlap the first storage capacitor plate CE1, with a secondgate insulating layer 105 therebetween. The second gate insulating layer105 may include an inorganic insulating layer such as SiOx, SiNx, orSiON.

The driving and switching TFTs T1 and T2 and the storage capacitor Cstmay be covered by an interlayer insulating layer 107. The interlayerinsulating layer 107 may be an inorganic layer including SiON, SiOxand/or SiNx. The data line DL may be on the interlayer insulating layer107. The data line DL is connected to the switching semiconductor layerAct2 of the switching TFT T2 via a contact hole passing through theinterlayer insulating layer 107.

The driving voltage line PL is on the interlayer insulating layer 107and may include a lower driving voltage line PL-1 and an upper drivingvoltage line PL-2. To provide a high-quality image or implement alarge-sized display device, a voltage drop resulting from resistance ofthe driving voltage line PL may be offset. According to an embodiment,since the driving voltage line PL includes the electrically connectedlower driving voltage line PL-1 and upper driving voltage line PL-2, avoltage drop of the driving voltage line PL may be prevented.

The lower driving voltage line PL-1 may include, for example, a samematerial as the data line DL. For example, the lower driving voltageline PL-1 may include Mo, Al, Cu, Ti, etc. and may be a multi-layer or asingle layer. In an embodiment, the lower driving voltage line PL-1 mayinclude a multi-layer of Ti/Al/Ti.

The lower driving voltage line PL-1 and the upper driving voltage linePL-2 are connected to each other via a contact hole in a firstinsulating layer 109 therebetween. The driving voltage line PL may becovered by a second insulating layer 111. The upper driving voltage linePL-2 may include Mo, Al, Cu, Ti, etc. and may be a multi-layer or asingle layer. In an embodiment, the upper driving voltage line PL-2 mayinclude a multi-layer of Ti/Al/Ti.

The second insulating layer 111 is a planarization insulating layerincluding an organic material. The organic material may include ageneral-purpose polymer such as an imide-based polymer,polymethylmethacrylate (PMMA) or polystyrene (PS), or polymerderivatives having a phenol-based group, an acryl-based polymer, an arylether-based polymer, an amide-based polymer, a fluorine-based polymer, ap-xylene-based polymer, a vinyl alcohol-based polymer, or a blendthereof. The first insulating layer 109 may include an organic material,examples of which are described above. In one embodiment, the firstinsulating layer 109 may include an inorganic material such as SiON,SiOx and/or SiNx.

The OLED may be on the second insulating layer 111 and may include apixel electrode 310, an opposite electrode 330, and an intermediatelayer 320 therebetween, the intermediate layer 320 including an emissionlayer.

A pixel-defining layer 113 may be on the pixel electrode 310 and maydefine a pixel by including an opening exposing the pixel electrode 310.The pixel-defining layer 113 may prevent an arc, etc., from occurringbetween the pixel electrode 310 and the opposite electrode 330, byincreasing the distance between the edge of the pixel electrode 310 andthe opposite electrode 330. The pixel-defining layer 113 may include,for example, an organic material such as PI or hexamethyldisiloxane(HMDSO).

The intermediate layer 320 may include a low molecular or polymermaterial. When the intermediate layer 320 includes a low molecularmaterial, the intermediate layer 320 may have a structure in which ahole injection layer (HIL), a hole transport layer (HTL), an emissionlayer (EML), an electron transport layer (ETL), an electron injectionlayer (EIL), etc. are stacked in a single or a composite configurationThe intermediate layer 320 may include one or more organic materials,e.g., copper phthalocyanine (CuPc),N,N′-Di(naphthalene-1-yl)-N,N′-diphenyl-benzidine (NPB), andtris-8-hydroxyquinoline aluminum (Alq3). These layers may be formed, forexample, by vacuum evaporation.

When the intermediate layer 320 includes a polymer material, theintermediate layer 320 may have a structure including an HTL and an EML.The HTL may include a PEDOT. The EML may include a polymer material suchas polyphenylene vinylene (PPV)-based material and a polyfluorene-basedmaterial. The structure of the intermediate layer 320 may have adifferent structure in another embodiment. For example, the intermediatelayer 320 may include a layer having one body over a plurality of pixelelectrodes 310 or may include a layer patterned to respectivelycorrespond to the pixel electrodes 310.

The opposite electrode 330 may be in the display area DA and may coverthe display area DA. For example, the opposite electrode 330 may haveone body over a plurality of OLEDs and correspond to the pixelelectrodes 310.

The OLED may be easily damaged by external moisture or oxygen. A thinfilm encapsulation layer 400 may cover the OLED as protection. The thinfilm encapsulation layer 400 may cover the display area DA and extend toan outside of the display area DA. The thin film encapsulation layer 400includes at least one organic encapsulation layer and at least oneinorganic encapsulation layer. For example, the thin film encapsulationlayer 400 may include a first inorganic encapsulation layer 410, anorganic encapsulation layer 430, and a second inorganic encapsulationlayer 420.

The first inorganic encapsulation layer 410 may cover the oppositeelectrode 330 and include SiOx, SiNx, and/or SiON. Other layers such asa capping layer may be between the first inorganic encapsulation layer410 and the opposite electrode 330. Since the first inorganicencapsulation layer 410 is along a structure thereunder, an uppersurface of the first inorganic encapsulation layer 410 is notplanarized.

The organic encapsulation layer 430 covers the first inorganicencapsulation layer 410. Unlike the first inorganic encapsulation layer410, an upper surface of the organic encapsulation layer 430corresponding to the display area DA may be approximately planarized.The organic encapsulation layer 430 may include at least one ofpolyethylene terephthalate (PET), polyethylene naphthalate (PEN),polycarbonate (PC), PI, polyethylene sulfonate, polyoxymethylene (POM),polyarylate, or HMDSO. The second inorganic encapsulation layer 420 maycover the organic encapsulation layer 430 and include SiOx, SiNx, and/orSiON.

Even when a crack occurs inside the encapsulation layer 400, the thinfilm encapsulation layer 400 may prevent the crack from being connectedbetween the first inorganic encapsulation layer 410 and the organicencapsulation layer 430, or between the organic encapsulation layer 430and the second inorganic encapsulation layer 420 via the above-describedmulti-layered structure. Therefore, the thin film encapsulation layer400 may prevent, reduce, or minimize formation of a path through whichexternal moisture or oxygen penetrates into the display area DA. Apolarization plate may be over the encapsulation layer 400 using a lighttransmissive adhesive. The polarization plate is a structure forreducing external light reflection. A layer including a black matrix anda color filter may be used for the polarization plate.

FIG. 4 illustrates an embodiment of a power voltage line and a secondinsulating layer. Referring to FIG. 4, as described with reference toFIGS. 3A and 3B, the second insulating layer 111, which is the organicinsulating layer, is in the display area DA and extends to thenon-display area NDA.

The second insulating layer 111 may include a division region IAcorresponding to the non-display area NDA. The division region IA is aregion in which the second insulating layer has been removed andsurrounds the display area DA. The division region IA may preventexternal moisture from penetrating into the display area DA along thesecond insulating layer 111 including the organic material. The secondinsulating layer 111 may be divided into a central portion 111 a and anouter portion 111 b by the division region IA.

The central portion 111 a corresponds to the display area DA and mayhave a greater area than that of the display area DA. In at least oneembodiment, the term “corresponding” may be understood to mean“overlapping.” The outer portion 111 b surrounds the central portion 111a in the display area DA and may surround the display area DA. At leastportions of the first power voltage line 10 and the second power voltageline 20 may overlap the division region IA.

One or more dams 121 and 123 may be in the division region IA. FIG. 4illustrates a structure in which two dams 121 and 123 are arranged. Thedams 121 and 123 may prevent an organic material from flowing in an edgedirection of the substrate 100 while the organic encapsulation layer 430(e.g., see FIGS. 3A and 3B) is formed. Thus, an edge tail of organicencapsulation layer 430 may not be formed.

Widths of the dams 121 and 123 may be less than the width of a powervoltage line, for example, the second power voltage line 20. In anembodiment, the width of the dam 121 may be less than the width of apower voltage line, for example, the second power voltage line 20 andmay be over the second power voltage line 20. In another embodiment, thedam 123 may overlap one edge of a power voltage line, for example, thesecond main voltage line 21 of the second power voltage line 20. In atleast one embodiment, the power voltage line may be understood to denoteat least one of the first power voltage line 10 or the second powervoltage line 20.

FIG. 5 illustrates an enlarged plan view of a portion V of the displaydevice of FIG. 4 and corresponds to a portion of a pull-off area POA ofFIG. 1 according to an embodiment. Also, FIG. 6 is a cross-sectionalview of the insert portion taken along a line VI-VI′ in FIG. 5 accordingto an embodiment. FIG. 7 is a cross-sectional view of the insert portiontaken along a line VII-VII′ of FIG. 5 according to an embodiment.

More specifically, FIG. 5 illustrates a portion of the pull-off area POAcorresponding to an upper portion of the division region IA, that is,the central portion 111 a as an inner pull-off area POA i. FIG. 5 alsoillustrate a portion of the pull-off area POA corresponding to a lowerportion of the division region IA, that is, the outer portion 111 b asan outer pull-off area POA o.

Referring to FIG. 5, the central portion 111 a and the outer portion 111b of the second insulating layer 111 are spaced apart from each other bythe division region IA. A portion of the power voltage line maycorrespond to the central portion 111 a. Another portion of the powervoltage line may correspond to the division region IA. Another portionof the power voltage line may correspond to the outer portion 111 b.

In an embodiment, the first main voltage line 11 of the first powervoltage line 10 may extend in a second direction to correspond to thecentral portion 111 a. The first connection line 12 may correspond tothe division region IA and the outer portion 111 b. A portion of thesecond main voltage line 21 of the second power voltage line 20 maycorrespond to the central portion 111 a. Remaining ones of the secondmain voltage line 21 and the second connection line 22 may correspond tothe division region IA and the outer portion 111 b.

Referring to FIGS. 6 and 7, the power voltage line may have amulti-layered structure including a first conductive layer and a secondconductive layer. For example, the first power voltage line 10 may havea two-layered structure including a first conductive layer 10 a and asecond conductive layer 10 b. The second power voltage line 20 may havea two-layered structure including a first conductive layer 20 a and asecond conductive layer 20 b.

The first conductive layers 10 a and 20 a of the first and second powervoltage lines 10 and 20, respectively, may include the same material asthe lower driving voltage line PL-1 and the data line DL described withreference to FIGS. 3A and 3B. The second conductive layers 10 b and 20 bof the first and second power voltage lines 10 and 20, respectively, mayinclude the same material as the upper driving voltage line PL-2described with reference to FIGS. 3A and 3B. In an embodiment, the firstconductive layers 10 a and 20 a and the second conductive layers 10 band 20 b may include the same material. For example, the first andsecond conductive layers 10 a, 20 a, 10 b, and 20 b may includeTi/Al/Ti.

The second conductive layers 10 b and 20 b may respectively and entirelycover the first conductive layers 10 a and 20 a. The second conductivelayers 10 b and 20 b may respectively and directly contact the firstconductive layers 10 a and 20 a and cover at least a portion of thefirst conductive layers 10 a and 20 a in the division region IA as inFIG. 6. For example, ends of the second conductive layers 10 b and 20 bcorresponding to the division region IA may cover lateral surfaces ofends of the first conductive layers 10 a and 20 a corresponding to thedivision region IA, extend further than the first conductive layers 10 aand 20 a, and directly contact layers (e.g. an interlayer insulatinglayer) below the first conductive layers 10 a and 20 a.

The second conductive layers 10 b and 20 b cover ends of the firstconductive layers 10 a and 20 a in the division region IA in FIG. 6. Inone embodiment, a structure in which the second conductive layers 10 band 20 b cover the ends of the first conductive layers 10 a and 20 a maybe applicable to a region excluding the division region IA, for example,the inner pull-off area POA i as in FIG. 7.

In one embodiment, a structure in which the second conductive layers 10b and 20 b cover the ends of the first conductive layers 10 a and 20 ais applicable to an outer pull-off area POA o. Although FIGS. 6 and 7illustrate a structure in which the second conductive layers 10 b and 20b cover the first conductive layers 10 a and 20 a not only in thedivision region IA but also in the inner and outer pull-off areas POA iand POA o, the same structure is applicable to other regions of thenon-display area NDA, not the pull-off area POA.

When the second conductive layers 10 b and 20 b cover ends of the firstconductive layers 10 a and 20 a, areas of the second conductive layers10 b and 20 b contacting the first conductive layers 10 a and 20 aincrease and thus may reduce resistance of the power voltage line. Thismay also prevent the first conductive layers 10 a and 20 a from beingdamaged while the second conductive layers 10 b and 20 b are patterned.For example, when the second conductive layers 10 b and 20 b arepatterned such that the second conductive layers 10 b and 20 b arerespectively located on only upper surfaces of the first conductivelayers 10 a and 20 a, the first conductive layers 10 a and 20 a may bedamaged by a gas used for etching (e.g. dry etching) of the secondconductive layers 10 b and 20 b. When the second conductive layers 10 band 20 b are patterned to cover the ends of the first conductive layers10 a and 20 a, damage to the first conductive layers 10 a and 20 a maybe prevented.

Referring to FIGS. 6 and 7, the first and second power voltage lines 10and 20 may be covered by a protective layer PVX in the division regionIA. The protective layer PVX covers the first and second power voltagelines 10 and 20 exposed via the division region IA. The protective layerPVX may include an inorganic insulating material including, for example,SiOx, SiNx, SiON, etc. The protective layer PVX may contact uppersurfaces of the first and second power voltage lines 10 and 20 in thedivision region IA as in FIG. 6 and contact an upper surface of thesecond insulating layer 111.

If the protective layer PVX is absent, portions of the first and secondpower voltage lines 10 and 20 corresponding to the division region IAmay be exposed to the outside until the thin film encapsulation layer400 is formed. The exposed first and second power voltage lines 10 and20 may be damaged by etchant used for patterning the pixel electrode 310(e.g., see FIGS. 3A and 3B) of the display area DA. Particularly, whenthe first and second power voltage lines 10 and 20 include aluminum, thefirst and second power voltage lines 10 and 20 may be damaged by theetchant.

The etchant damages metal such as aluminum in the first and secondconductive layers 10 a, 20 a, 10 b, and 20 b forming the first andsecond power voltage lines 10 and 20. To prevent damage by the etchant,the design may be partially changed, for example, so that the secondconductive layers 10 b and 20 b, which are uppermost layers from amongconductive layers of the first and second power voltage lines 10 and 20,overlap portions of the first conductive layers 10 a and 20 a. Also, anadditional dam may be formed to extend in the first direction and toconnect dams 121 to 123. However, the additional dam connecting dams 121and 123 may provide a path via which external moisture penetrates.Furthermore, since areas of the second conductive layers 10 b and 20 bare reduced compared to areas of the first conductive layers 10 a and 20a, there is limit in reducing resistance of a power voltage line towhich a relatively high DC voltage is applied.

However, according to one or more embodiments, the protective layer PVXcovers the first and second power voltage lines 10 and 20 exposed viathe division region IA. Thus, the above-described damage by the etchantmay be prevented and the design of the second conductive layers 10 b and20 b does not need to be changed. Therefore, the damage of the powervoltage line may be prevented while resistance of the power voltage lineis reduced or minimized.

The first and second power voltage lines 10 and 20 are covered by theprotective layer PVX in the division region IA and are not exposed tothe outside. As described above, damage to the first and second powervoltage lines 10 and 20 may be prevented during a process such as aprocess of forming the pixel electrode 310.

The protective layer PVX may be formed, for example, by chemical vapordeposition (CVD) after a portion of the second insulating layer 111corresponding to the division region IA. The protective layer PVX mayextend not only to the first and second power voltage lines 10 and 20exposed via the division region IA, but also to an upper surface of thesecond insulating layer 111. For example, in FIG. 7, the protectivelayer PVX may cover the central portion 111 a of the second insulatinglayer 111 and at least a portion of the upper surface of the outerportion 111 b of the second insulating layer 111.

Portions of the first and second power voltage lines 10 and 20corresponding to the division region IA may be covered by the thin filmencapsulation layer 400, while overlapping the thin film encapsulationlayer 400 via the division region IA. At least one of the dams 121 and123 may prevent the organic encapsulation layer 430 of the thin filmencapsulation layer 400 from flowing in an edge direction of thesubstrate 100. The first and second inorganic encapsulation layers 410and 430 may extend to the outer pull-off area POA o to cover thedivision region IA. The dams 121 and 123 may include the same materialas that of the second insulating layer 111.

FIG. 8 illustrates a cross-sectional view of an insert portion accordingto a modified embodiment of FIG. 7. Referring to FIG. 8, an additionalinsulating layer may be further arranged over the central portion 111 aand the outer portion 111 b of the second insulating layer 111.

For example, the pixel-defining layer 113 (e.g., see FIGS. 3A and 3B) ofthe display area DA may extend to the pull-off area POA. Thepixel-defining layer 113 may include a first insulating portion 113 aand a second insulating portion 113 b The first insulating portion 113 amay correspond to the central portion 111 a of the second insulatinglayer 111. The second insulating portion 113 b may correspond to theouter portion 111 b of the second insulating layer 111. Thepixel-defining layer 113 may include a separation region OAcorresponding to the division region IA of the second insulating layer111. The first insulating portion 113 a may be spaced apart from thesecond insulating portion 113 b by the separation region OA. Theseparation region OA may have a size equal to or less than that of thedivision region IA.

The dam 121 may include first and second dam layers 121 a and 121 brespectively under and on the protective layer PVX, and the dam 123 mayinclude first and second dam layers 123 a and 123 b respectively underand on the protective layer PVX. The first dam layers 121 a and 123 amay include the same material as the second insulating layer 111. Thesecond dam layers 121 b and 123 b may include the same material as thepixel-defining layer 113 (e.g., see FIGS. 3A and 3B).

FIG. 9 illustrates the insert portion according to a modified embodimentof FIG. 5. Referring to FIG. 9, the central portion 111 a of the secondinsulating layer 111 may further include an auxiliary division regionSI. For example, the central portion 111 a may further include theauxiliary division region SI between a portion of the first powervoltage line 10 and a portion of the second power voltage line 20. Thecentral portion 111 a may include a first central portion 111 a-1overlapping a portion of the first power voltage line 10 divided by theauxiliary division region SI, a portion of the second power voltage line20, and a second central portion 111 a-2. Like the division region IA,the auxiliary division region SI may prevent penetration of externalmoisture.

Example embodiments have been disclosed herein, and although specificterms are employed, they are used and are to be interpreted in a genericand descriptive sense only and not for purpose of limitation. In someinstances, as would be apparent to one of ordinary skill in the art asof the filing of the present application, features, characteristics,and/or elements described in connection with a particular embodiment maybe used singly or in combination with features, characteristics, and/orelements described in connection with other embodiments unless otherwiseindicated. Accordingly, various changes in form and details may be madewithout departing from the spirit and scope of the embodiments set forthin the claims.

What is claimed is:
 1. A display device, comprising: a substrateincluding a non-display area adjacent to a display area; a thin filmtransistor in the display area; a display element electrically connectedto the thin film transistor; a thin film encapsulation layer coveringthe display element; a power voltage line in the non-display area; anorganic insulating layer covering a part of the power voltage line andincluding an opening region that exposes another part of the powervoltage line; and a protective layer covering an upper surface of thepower voltage line in the opening region.
 2. The display device asclaimed in claim 1, wherein the protective layer contacts a portion ofthe upper surface of the power voltage line in the opening region. 3.The display device as claimed in claim 1, wherein the thin filmencapsulation layer includes an inorganic encapsulation layer and anorganic encapsulation layer.
 4. The display device as claimed in claim3, wherein an end of the inorganic encapsulation layer extends towardbeyond the opening region.
 5. The display device as claimed in claim 3,wherein the inorganic encapsulation layer contacts the protective layer.6. The display device as claimed in claim 5, wherein the protectivelayer includes an inorganic insulating material.
 7. The display deviceas claimed in claim 5, wherein a contact region between the inorganicencapsulation layer and the protective layer is located in the openingregion.
 8. The display device as claimed in claim 1, wherein the powervoltage line includes: a first conductive layer; and a second conductivelayer on the first conductive layer.
 9. The display device as claimed inclaim 8, wherein the width of the second conductive layer is greaterthan that of the first conductive layer.
 10. The display device asclaimed in claim 8, wherein: an end of the second conductive layerextends beyond an end of the first conductive layer, and the end of thesecond conductive layer contacts an upper surface of an insulating layerthat is located between the first conductive layer and the substrate.11. The display device as claimed in claim 8, wherein the secondconductive layer entirely covers an upper surface of the firstconductive layer.
 12. The display device as claimed in claim 8, whereinat least one of the first conductive layer or the second conductivelayer includes a multi-layer.
 13. The display device as claimed in claim12, wherein the multi-layer includes a first layer including titanium, asecond layer including aluminum, and a third layer including titanium.14. The display device as claimed in claim 1, wherein the opening regionsurrounds the display area.
 15. The display device as claimed in claim14, further comprising a dam in the opening region and an organicinsulating material.
 16. The display device as claimed in claim 15,wherein the dam surrounds the display area.
 17. The display device asclaimed in claim 1, wherein the display element includes an organiclight-emitting diode diode